}

    @Test
    @DisplayName("Should handle whitespace delimiter")
    void testJoinWithWhitespaceDelimiter() {
        String result = StringUtil.join("   ", "spaced", "out");
        assertEquals("spaced   out", result);
    }

    @Test
    @DisplayName("Should handle elements containing delimiter")
    void testJoinElementsContainingDelimiter() {

    /**
     * Happy-path: a filter that accepts any name.
     */
    @ParameterizedTest
    @DisplayName("accepts any non-null/any string")
    @ValueSource(strings = { "file.txt", "data.DAT", "a", "x.y.z", "  spaced  " })
    void acceptsAnyNameReturnsTrue(String input) throws Exception {
        SmbFilenameFilter filter = (dir, name) -> true;

        boolean result = filter.accept(mockDir, input);

        // Leading and trailing spaces
        value = " value1 , value2 , value3 ";
        result = KuromojiCSVUtil.parse(value);
        assertEquals(3, result.length);
        assertEquals(" value1 ", result[0]);
        assertEquals(" value2 ", result[1]);
        assertEquals(" value3 ", result[2]);

        // Spaces in quoted values
        value = "\" spaced value \",\"  another  \"";

        bb.put("\\\\server\\\\share".getBytes(StandardCharsets.UTF_16LE));
        bb.putShort((short) 0);

        bb.position(60); // Properly spaced
        bb.put("\\\\alt\\\\path".getBytes(StandardCharsets.UTF_16LE));
        bb.putShort((short) 0);

        bb.position(90); // Properly spaced
        bb.put("NODE01".getBytes(StandardCharsets.UTF_16LE));
        bb.putShort((short) 0);

    assertEquals("string with spaces", spaceEscaper.escape("string with spaces"));
  }

  /** Tests that if we add extra 'safe' characters they remain unescaped */
  public void testCustomEscaper() {
    UnicodeEscaper e = new PercentEscaper("+*/-", false);
    for (char c = 0; c < 128; c++) {
      if ((c >= '0' && c <= '9')
          || (c >= 'a' && c <= 'z')
          || (c >= 'A' && c <= 'Z')

    assertEquals("string with spaces", spaceEscaper.escape("string with spaces"));
  }

  /** Tests that if we add extra 'safe' characters they remain unescaped */
  public void testCustomEscaper() {
    UnicodeEscaper e = new PercentEscaper("+*/-", false);
    for (char c = 0; c < 128; c++) {
      if ((c >= '0' && c <= '9')
          || (c >= 'a' && c <= 'z')
          || (c >= 'A' && c <= 'Z')

        // Test that non-space characters in padding are preserved in length calculation
        byte[] src = new byte[100];
        src[0] = 0x20;

        // Encode "AB" followed by non-space padding
        src[1] = 'E';
        src[2] = 'B'; // A
        src[3] = 'E';
        src[4] = 'C'; // B

        // Use 'X' (0x58) instead of space for padding
        for (int i = 5; i < 31; i += 2) {

        // Default constructor
    }

    /**
     * Quotes a string value if it contains spaces.
     * Multi-word values are wrapped in double quotes with internal quotes replaced by spaces.
     *
     * @param value the string value to quote
     * @return the quoted string if it contains spaces, otherwise the original value
     */
    protected String quote(final String value) {

        return fessConfig.isCrawlerDocumentDuplicateTermRemoved();
    }

    /**
     * Gets the array of space character codes from configuration.
     *
     * @return array of character codes to be treated as spaces
     */
    protected int[] getSpaceChars() {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();

 * higher space consumption.
 *
 * <p>This class extends {@link Number}, but does not define methods such as {@code
 * equals}, {@code hashCode} and {@code compareTo} because instances are expected to be mutated, and
 * so are not useful as collection keys.
 *
 * <p>jsr166e note: This class is targeted to be placed in java.util.concurrent.atomic.
 *
 * @since 1.8